Spectrum technology is a relatively new high-tech field which incorporates optics, spectroscopy, precision machinery, electronics technology and computer techniques. Spectrum technology assists a user to obtain plenty of information pertaining to a space or a spectrum. Because of this great advantage, spectrum technology has numerous applications in pursuits such as navigation, scientific experimentation, industrial manufacturing, agriculture, geology, oceanography, and safety devices. Similarly, spectrum technology already has a great reputation in the development of optical instruments.
A spectrograph is an essential piece of equipment for performing spectrum analysis. Analyzing a spectrum can provide information about elements composing a substance, and can show information about energy levels or the interaction between energy levels in an atom. To find out the structure of an atom or a molecule, spectrum analysis is a key method. Most knowledge of atomic structures is obtained from the early analysis of atomic spectra.
A conventional spectrograph separates electromagnetic radiation having short wavelengths into its spectral components. Generally, such spectrograph comprises a collimating system, a dispersing system and a receiving system. The dispersing system of a grating spectrograph is a diffractive optical grating device. A typical grating spectrograph is disclosed in “A New Way of Multiple Paths Spectrograph-medium-level Spectrograph” (Spectroscopy and Spectrum Analysis; April 1991). As represented in FIG. 3 hereof, the grating spectrograph comprises the following components along a continuous optical path: a light source 1, an entrance slit plate 2, a collimator 3, a diffractive optical grating device 4, an aspherical lens 5, a planar mirror 6, an exit slit plate 7, a light detector 8, and an imaging device 9.
The operational flow of the grating spectrograph is as follows. The light source 1 generates light beams. The light beams pass through the entrance slit plate 2. After being made parallel by the collimator 3, the light beams directly enter the diffractive optical grating device 4. The diffracted light beams then pass through the aspherical lens 5 having a planar surface and a curved surface. The light beams are thus separated and corrected to form a two-dimensional spectrum. The light beams are then reflected by the planar mirror 6 to a focal plane having the exit slit plate 7 located thereon. The exit slit plate 7 has a plurality of exit holes for the light beams to pass through. The light beams pass through the exit holes of the exit slit plate 7. The light detector 8 performs spectrum analysis of the light beams. Finally, the light beams are output by the light detector 8 and imaged by the imaging device 9.
The light detector 8 is conventionally a photoelectric detector such as a photomultiplier. The photomultiplier detects the intensity of the light beams passing through the exit slit plate 7. However, in each detecting step, the photomultiplier can only obtain optical data of one wavelength point. That is, the photomultiplier cannot obtain optical data of a number of wavelength points simultaneously, nor even within the space of a few microseconds.
In general, to achieve the measurement of a plurality of wavelength points, a precision machine driving a machinery scanner is provided to assist the photomultiplier. In such driving, however, the data of all wavelength points still cannot be measured within the space of a few microseconds. Furthermore, the intensities of the light beams cannot be wholly detected if they are continuously varied.
Since the 1960s, in addition to a photomultiplier, a charged coupled device (CCD) has been applied in a typical spectrograph. The CCD analyzes a spectrum according to the following operational steps. When the CCD is exposed to a plurality of light beams, each CCD unit stores charges proportional to its exposure. If a pulse having a specific sequence is applied to the CCD, the stored charges of the CCD unit can be directionally transmitted in the CCD, and a self-scanning step can be performed. The stored charges are then transmitted out step by step.
The CCD is able to detect data of a plurality of wavelength points in a specific wavelength range. If the output stored charges due to the pulse are A/D (analog-to-digital) transformed and then sequentially input to a computer, the computer can gather, analyze and process the transformed charges. The screen of the computer then shows the distribution graph of the light intensity of the transformed charges, and a fast spectrum analysis is thereby provided.
However, both the CCD and the photomultiplier transform optical signals (the light beams from the light source) into electrical signals for a computer to subsequently process. The requirement of transformation from optical signals to electrical signals limits the photomultiplier or CCD to be sensitive only to wavelengths in the range from 200 nm to 1100 nm. Outside of the above range, the data of the wavelength points cannot be obtained.
What is need, therefore, is an optical processor which overcomes the above-mentioned problems.